Guaran partial hydrolysis

Partial hydrolysis is also useful in the study of some problems connected with heteroglycans. Whistler and Durso hydrolyzed guaran to 79 % completion and isolated 4-0-/3-D-mannopyranosyl-D-mannose, 6-0-a-n-galacto-pyranosyl-D-mannose, and 6-0-a-D-galactopyranosyl-4-0- 3-D-mannopyran-osyl-D-mannose from the hydrolysate. This enabled an unambiguous... 

In 1951, Whistler and Durso reported68 the isolation of epimelibiose by partial, acid hydrolysis of the polysaccharide guaran, followed by charcoal-column fractionation of the products. ThA material was obtained in anhydrous crystalline form from a mixture of methyl and butyl alcohols it had m.p. 201°, [a]26D + 120.9° — +124.6° in 36 hr. (c 2, in water). The yield was 2.2% of the weight of guaran used. Epimelibiose has also been produced72" in crystalline form following the ammonia-catalyzed alkaline isomerization of melibiose. 

Preparation. The sugar may be prepared by charcoal-column fractionation of the partial acid hydrolysis products of guaran (4 ) and by the alkaline isomerization of melibiose ( S). 

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